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  <title>Document</title>
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<body>
  
  <script>
    // 1.var声明的变量会进行作用域的提升
    // console.log(message)
    // var message = "Hello World"

    // 2.let/const声明的变量: 没有作用域提升
    // console.log(address)
    console.log(address)
    let address = "广州市"
    const info = {}

  </script>

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